In a neuron, what is the primary function of the myelin sheath?

• A. It increases the speed of action potential conduction by insulating the axon and enabling saltatory conduction between nodes of Ranvier.
• B. It contains the nucleus and organelles that maintain the neuron's metabolic functions.
• C. It forms the postsynaptic receptors that detect neurotransmitters at chemical synapses.
• D. It synthesizes neurotransmitters and packages them into synaptic vesicles for release at the axon terminal.

Answer: (A)

Verified step by step guidance

1. Step 1: Understand the structure of a neuron, which includes the cell body (soma), dendrites, axon, and axon terminals.
2. Step 2: Identify the role of the myelin sheath, which is a fatty layer that wraps around the axon of many neurons.
3. Step 3: Recognize that the myelin sheath acts as an insulator, preventing ion leakage and allowing electrical signals to travel more efficiently along the axon.
4. Step 4: Learn about saltatory conduction, where the action potential jumps from one node of Ranvier (gaps in the myelin sheath) to the next, greatly increasing the speed of signal transmission.
5. Step 5: Differentiate the myelin sheath's function from other neuron components, such as the nucleus (metabolic functions), postsynaptic receptors (detect neurotransmitters), and synaptic vesicles (store neurotransmitters).